<template>

  <div class="app-container">

    <h2 style="text-align: center;">发布新课程</h2>

    <el-steps :active="1" process-status="wait" align-center style="margin-bottom: 40px;">
      <el-step title="填写课程基本信息"/>
      <el-step title="创建课程大纲"/>
      <el-step title="最终发布"/>
    </el-steps>

    <el-form label-width="120px">

      <el-form-item label="课程标题">
        <el-input v-model="courseInfo.title" placeholder=" 示例：机器学习项目课：从基础到搭建项目视频课程。专业名称注意大小写"/>
      </el-form-item>

      <!-- 所属分类：级联下拉列表 -->
      <!-- 一级分类 -->
      <el-form-item label="课程类别">
        <el-select v-model="courseInfo.subjectParentId" placeholder="一级分类" @change="selectChangeTwo">
          <el-option v-for="subject in subjectNestedList" :key="subject.id" :label="subject.title" :value="subject.id"/>
        </el-select>

        <!-- 二级分类 -->
        <el-select v-model="courseInfo.subjectId" placeholder="二级分类">
          <el-option v-for="subject in subSubjectList" :key="subject.value" :label="subject.title" :value="subject.id"/>
        </el-select>
      </el-form-item>
      

      <!-- 课程讲师 -->
      <el-form-item label="课程讲师">
        <el-select
          v-model="courseInfo.teacherId"
          placeholder="请选择">
          <el-option
            v-for="teacher in teacherList"
            :key="teacher.id"
            :label="teacher.name"
            :value="teacher.id"/>
        </el-select>
      </el-form-item>

      <!-- 课时 -->
      <el-form-item label="总课时">
        <el-input-number :min="0" v-model="courseInfo.lessonNum" controls-position="right" placeholder="请填写课程的总课时数"/>
      </el-form-item>

      <!-- 课程简介 TODO -->
      <el-form-item label="课程简介">
        <!-- <el-input v-model="courseInfo.description" placeholder=""/> -->
        <tinymce :height="300" v-model="courseInfo.description"/>
      </el-form-item>

      <!-- 课程封面 TODO -->
      <!-- 课程封面-->
      <el-form-item label="课程封面">

        <el-upload
          :show-file-list="false"
          :on-success="handleAvatarSuccess"
          :before-upload="beforeAvatarUpload"
          :action="BASE_API+'/eduoss/fileoss'"
          class="avatar-uploader">
          <img :src="courseInfo.cover" style="width: 180px;height: auto;">
        </el-upload>

      </el-form-item>

      <el-form-item label="课程价格">
        <el-input-number :min="0" v-model="courseInfo.price" controls-position="right" placeholder="免费课程请设置为0元"/> 元
      </el-form-item>

      <el-form-item>
        <el-button :disabled="saveBtnDisabled" type="primary" @click="saveOrUpdate">保存并下一步</el-button>
      </el-form-item>
    </el-form>
    
  </div>
</template>

<script>
import course from '@/api/edu/course'
import { getSubjectList } from '@/api/edu/subject'
import Tinymce from '@/components/Tinymce'

export default {
  components: { Tinymce },  // 引入组件
  data(){
    return{
      saveBtnDisabled: false,
      courseInfo: {
        title: '',
        subjectId: '',
        subjectParentId: '',
        teacherId: '',
        lessonNum: 0,
        description: '',
        cover: '/static/109951166046433599.jpg',
        price: 0
      },
      courseId: '',
      BASE_API: process.env.BASE_API,
      teacherList: [],
      subjectNestedList: [],//一级分类列表
      subSubjectList: []//二级分类列表
    }
  },
  created(){

    if (this.$route.params && this.$route.params.id) {
      this.courseId = this.$route.params.id;
      this.getInfo()
    } else{
      this.getSubjectList();
    }
    this.getListTeacher();

  },
  methods:{
    getInfo(){
      course.getCourseInfoId(this.courseId)
        .then(res =>{
          this.courseInfo = res.data.courseInfoVO

          // 查询所有分类
          getSubjectList()
            .then(res =>{
              this.subjectNestedList = res.data.list  // 所有一级分类

              for (let i = 0; i < this.subjectNestedList.length; i++) {
                var oneSubject = this.subjectNestedList[i];
                
                if (this.courseInfo.subjectParentId == oneSubject.id) {
                  this.subSubjectList = oneSubject.children
                }
              }
            })
        })
    },

    handleAvatarSuccess(res, file) {
      this.courseInfo.cover = res.data.url
    },

    beforeAvatarUpload(file) {
      const isJPG = file.type === 'image/jpeg'
      const isLt2M = file.size / 1024 / 1024 < 2

      if (!isJPG) {
        this.$message.error('上传头像图片只能是 JPG 格式!')
      }
      if (!isLt2M) {
        this.$message.error('上传头像图片大小不能超过 2MB!')
      }
      return isJPG && isLt2M
    },

    selectChangeTwo(value){
      console.log(value);
      this.courseInfo.subjectId = ''

      // 传入当前select的选中
      for (let i = 0; i< this.subjectNestedList.length; i++) {
        let oneSubject = this.subjectNestedList[i];

        if (value === oneSubject.id) {
          // 从一级分类中获取二级分类
          this.subSubjectList = oneSubject.children
        }
      }
    },

    // 查询所有讲师
    getListTeacher(){
      course.getListTeacher()
        .then(res => {
          this.teacherList= res.data.items
        })
    },

    getSubjectList(){
      getSubjectList()
        .then(res =>{
          this.subjectNestedList = res.data.list;
        })
    },

    saveOrUpdate(){
      if (!this.courseInfo.id) {
        this.addCourse()
      } else {
        this.updateCourse()
      }
    },

    addCourse(){
      course.addCourseInfo(this.courseInfo)
        .then(res=>{
          this.$message({
            type: 'success',
            message: '添加课程信息成功！'
          })
          this.$router.push({ path:'/edu/course/chapter/' + res.data.courseId})
        })
    },

    updateCourse(){
      course.updateCourseInfo(this.courseInfo)
        .then(res =>{
          this.$message({
            type: 'success',
            message: '修改课程信息成功！'
          })
          this.$router.push({ path:'/edu/course/chapter/' + this.courseId})
        })
    }
  }
}
</script>

<style scoped>
  .tinymce-container {
    line-height: 29px;
  }
</style>